Piston and connecting-rod



H. D. MORTON.

PISTON AND CONNECTING'ROD.

APPLICATION FILED APR. 12. 1917.

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Patented Jan. 11,1921.

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TED STTES PTE OFFICE.

HARRY D. MORTON, OF DETROIT, MICHIGAN;

IPISTON AND CONNECTING-ROD.

To all whom it may concern Be it known that T, HARRY D. MonroN, acitizen of the United States, residin at Detroit, Wayne county, State ofMichigan, have invented certain new and useful Tmprovements in Pistonsand Connecting- Rods, of which the following is a specification.

My invention relates to a welded steel piston and connecting rod and themethod of making the same.

The principal objects of my invention are to produce a light, simple andinexpensive piston and connecting rod assembly suitable for use ininternal combustion engines and provided with long bearing surfaces.

The above and other objects and the novel features of my invention willbe apparent from the following description taken in connectionwith thedrawing, which constitutes a part of this invention and in which,

Figure 1 is a vertical sectional view of a combined piston andconnecting rod assenr bly embodying my invention; 7

Fig. 2 is a side elevation of the same; and

Fig. 3 is a central sectional view, on a smaller scale, of a pistonshell embodying my invention.

Referring to the drawing, the shell S of the cylinder is pressed fromsheet steel, being closed at the upper end and open at the lower end.After the shell has been formed, depressions 10 are formed indiametrically opposite sides thereof and holes 11 are then punchedthrough the bottoms of these depressions to receive the piston pin 12.The holes 11 are of smaller diameter than the depressions 10 so that anangular portion of the depression is left which surrounds the hole.After the holes 11 have been punched in the shell the ring grooves 13are rolled therein. These grooves are adapted to receive the usualpiston rings.

I A band 14, preferably of cast iron is also attached to the shell S atits lower open end, the band being provided with a groove to receive thelower edge of the shell and the metal of the band being fused to theshell.

Owing to the great difference in coeflicients of expansion as betweenaluminum alloys and cast iron, it is necessary, where such aluminumalloy pistons are employed, that they be made considerably smaller thanthe bore of the cylinder. The result is that Specification of LettersPatent noise and loss of power.

Patented Jan. 11, 1921. 1917. Serial No. 161,588.

until this loose fitting piston has become heated to a point where itfits the cylinder properly, there is considerable side slap The band 14on the lower end of the sheet steel piston S is designed to fit closelyin the cylinder while the upper end of the piston floats on the pistonrings in the grooves 13. It will, of course, be possible withoutdeparting from the spirit of my invention to fuse another cast iron bandto the upper end of the piston shell S, similar to the band 14, thusforming at either end a close fitting bearing for such piston. Inasmuchas the coeficient of expansion of steel more closely approaches that ofcast iron than does the coefficient of expansion of aluminum and itsalloys, it is apparent that with the construction T have shown thenecessity for a loose it of piston in the cylinder is greatly minimized.

The connecting rod and associated parts include an upper bearing forging15 which is made in one piece and has an elongated barrel 16 which issubstantially as long as the distance between the openings 11 inopposite sides of the shell. The bearing forging 15 also has a hollowboss 17 at one side thereof. The connecting rod proper consists of ahollow tube 18 adapted to slip over a reduced portion 19 of the boss 17and to abut against an exterior shoulder 20 on the boss. The end of thetube 18 abuts against the shoulder 20 only at the inner edge thereof andthe shoulder and end of the tube are shaped so as to form a taperingroove to receive welding material 21 whic is deposited in the groove bya metallic electrode electric arc welding apparatus.

The forging 22 which forms theupper half of the lower connecting rodbearing is provided with a hollow boss 23 and the lower end of the tube18 is welded to the boss 23 in the same manner as the bearing 15 by theweld 24. The annular welds 21 and 24 are formed before the connectingrod and its bearings are assembled with the piston shell and after theannular welds 21 and 24 are completed the surplus metal is machinedaway. so as to provide a smooth joint.

When the connecting rod and its bearings have been assembled a suitablebearing bushing 25 is inserted into the barrel 16 of the bearing forging15. The bearing forging 15 carrying the bushing 25 is then inserted intothe shell through the open end thereof so that its barrel 16 will beaxially in line with the openings 11, 11 of the shell. The hollow pistonpin 12 is then inserted through one of the openings, and through thebushing 25 and the other opening so as to hold the parts together. Itwill be seen that the piston pin 12 rests on the edges of the openings11, 11 and that the ends project therethrough and form grooves g withthe walls 26 of the remainingzportions of the depressions in the shellS. In order to permanently unite the piston pin 12 to the shell S Ideposit molten metal m in the grooves g by means of a metallic electrodeelectric arc welding apparatus. The welding material m unites with boththe shell and the pin and a perfect joint is provided. After the welds mare completed the surplus metal is machined away and the ring grooves 13and 14 are also machined. The annular welds m do not appear in Fig. 2because the ioints thereof disappear when the Iy are machined.

he advantages of my construction are as follows: A

The operations necessary to production of this assembly, on a largescale, are very simple and inexpensive to carry out.

The weight of the assembly is only about 4.0% of that of the usual ironpiston and forged steel connecting-rod.

The cost of materials is very much less than that of aluminum alloypistons, which alone can approach this construction in lightness.

Owing to the difiiculty experienced in satisfactorily attaching theupper end of the connecting rod to the piston pin, where ordinary pistonand connecting rod construction is used, this point is one of the mosttroublesome in gasolene engine design. In my construction, however, thisdifiiculty is overcome, by reason of the fact that the piston pin isintegral with the piston, and the upper end of the connecting rod moveson the piston pin. This affords a much longer bearing for the upper endof the connecting rod than is possible by the ordinary construction. Thehollow bosses 23, 17 and the tubular connecting rod uniting them providemeans whereby oil from the crank case may circulate to the bearingbushing 25 and more effectively lubricate the same.

While I have shown and described my invention in detail I do not wish tobe limited to the exact form illustrated as it is obvious that variouschanges may be made therein within the spirit and scope of theinvention.

Having thus described the invention,

what is claimed and desired to be secured by Letters Patent is:

l. A piston comprising a hollow sheet metal cylindrical shell having ahead and diametrically opposite circular openings in its cylindricalwall, said wall also having inwardly extending portions surrounding saidopenings, a piston pin having the ends thereof resting on the edges ofsaid openings and forming grooves with said inwardly extending portions,and welding material in said grooves uniting said piston pin to saidshell.

2. A. piston comprising a hollow sheet metal cylindrical shell closed atits upper end and open at its lower end, said shell having diametricallyopposite circular openings in its cylindrical wall, said wall havinginwardly extending angular portions surrounding said openings and alsohaving ring grooves therein above said openings, a hollow piston pinhaving the ends thereof resting in contact with the edges of saidopenings and forming outwardly facing grooves with said angularportions, welding material in said grooves uniting the ends of saidpiston pin to said shell, and a band attached to the lower open end ofthe shell.

3. A combined piston and connecting rod comprising a sheet metalcylindrical shell having diametrically opposite openings in its wall, apiston pin having the ends thereof extending through said openings,welding material uniting the ends of said piston pin to said shell, abushing surrounding said piston pin, a forging carried by said bushing,and a connecting rod welded at one end to said-forging. 1

4. A combined piston and connecting rod for internal combustion enginescomprising a hollow sheel metal cylindrical shell closed at its upperend and open at its lower end, said shell having diametrically oppositecircular openings in its cylindrical wall and inwardly extendingportions in the wall surrounding said openings, a hollow piston pinhaving the ends thereof supported by the edges of said openings andforming grooves with said inwardly extending portions of the shell,welding material in said grooves uniting said piston pin to said shell,a bushing surrounding said" "piston pin and extending from adjacent oneof said openings to a point adjacent the other opening, aonepiecebearing forging carried by said bushing and substantially the samelength as the bushing, said forging having a hollow boss, and aconnecting rod having one end welded to the boss of said forging.

In testimony whereof I aflix my signature.

HARRY D. MORTON.

